Reviews 



Ueber Erythrosuchus, Vertreter der neuen Reptilordnung Pelyco- 

 simia. By F. von Huene. Geologische und paleontologische 

 Abhandlungen, X (191 1). Pp. 58; plates 11. 

 The genus Erythrosuchus was described five years ago by Dr. R. 

 Broom, from the Triassic of South Africa; it was referred by him to 

 the Phytosauria, from which it differs especially in having terminal 

 nares and short premaxillae. Dr. Heune, after a careful study of the 

 known remains of the genus, reaches, in the above-cited paper, the 

 startling conclusion that the genus represents a new order of reptiles 

 allied to the Pelycosauria ; that is, that it is a branch from the root- 

 stem of that group ("Zweig von der Wurzel der Pelycosaurien"). 

 Aside from the differential characters already mentioned, Erythrosuchus 

 differs from the phytosaurs chiefly in the structure of the limbs, which 

 seem to resemble more those of the pelycosaurs and other primitive 

 reptiles. The skull, as Huene admits, has "viele und auffallende 

 Ubereinstimmungen mit den Phytosaurien, " in its two temporal 

 vacuities, the absence of additional temporal bones, antorbital vacui- 

 ties, etc. The vertebrae also, are of the archosaurian type, differing 

 especially from those of the Pelycosauria in the shallow concavities of 

 their centra, the absence of intercentra, and especially in the articula- 

 tion of the dorsal ribs. It is an important fact, which the author does 

 not seem to appreciate, that the mode of rib articulation is highly 

 characteristic of the reptilian orders. It may be set down as a funda- 

 mental taxonomic principle that no related groups of reptiles, or other 

 vertebrates differ materially in the way in which the dorsal ribs articu- 

 late with their vertebrae. All the archosaurian reptiles are alike in 

 this respect — double-headed ribs articulating with the diapophyses of 

 the arches exclusively, at least posteriorly — a character found in no 

 other vertebrates. And this is the condition in Erythrosuchus, a char- 

 acter in itself sufficient to fix its position among the Archosauria, and 

 by Archosauria I mean the Crocodilia, Dinosauria, Pterosauria, and 

 Parasuchia. The Sauropterygia, it is true, also have the dorsal ribs 

 attached exclusively to the diapophyses, but the ribs show no division 

 into capitulum and tuberculum, differentiating the order sharply. 

 Under the Sauropterygia I include only the Nothodontia and Plesio- 

 sauria — the Mesosauria, which are sometimes included in the order, 



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